A crime is the violation of the right(s) of other men by force (or fraud). It is only the initiation of physical force against others- i. e., the recourse to violence- that can be classified as a crime in a free society (as distinguished from a civil wrong). Ideas, in a free society, are not a crime- and neither can they serve as the justification of a crime.

The New Left: The Anti-Industrial Revolution (1971)